Brugada syndrome

An autosomal dominant genetic disorder with variable penetrance.

Rare disorder that can be unmasked by medications causing sodium channel blockade.

Associated with loss of function mutations in the gene encoding SCN5A, the alpha subunit of the cardiac sodium channel (Antzelevitch C et al).

Impaired sodium channels reduce inward sodium current in some myocardial cells and decreases the action potential duration in such cells.

All myocardial cells are not affected equally with most cells affected in the right ventricle.

Right Bundle Branch Block, with persistent ST Segment Elevation and Sudden Cardiac Death.

Impaired sodium channels associated with non-uniformed repolarization throughout the myocardium, and especially the right ventricle.

Mutations in cardiac sodium channel SCN genes are predominant, but changes in potassium, calcium, and trafficking genes have been noted.

Associated with ST-segment elevation.

Associated with increased of ventricular tachyarrhythmias.

More common in Asians.

Prevalence in US 0.4%.

Male:female ratio 9:1.

Accounts for approximately 4% of all sudden cardiac deatha and 20% of sudden cardiac death in the absence of structural cardiac disease.

ECG findings most often described as a pseudo-right BBB with persistent ST-segment elevation in leads V1 through V3.

ECG characterized by a peculiar form of ST segment elevation in leads V1-V3.

ECG manifestations include a pseudo-right bundle branch block, and ST-segment elevation in the right precordial leads.

ECG abnormalities may be transient but become manifests with fever, electrolyte changes, medications such as tricyclic antidepressants or sodium channel blockers.

cardiac imaging evaluation usually normal in this process.

When the pattern is accompanied by history of syncope, ventricular arrhythmias, suspicious family history the diagnosis can be made.

Two patterns of ECG: Type I classic syndrome with sharp initial deflection of r-prime in leads V1-V3 and smooth descent of ST segment into inverted t-wave-“sail sign”.Type 2 and 3 have saddle back ST segment elevation V1-V3 with type 2 having greater than 1 mm ST-segment elevation and type 3 less than 1 mm.

Associated with syncope and positive family history.

ECG findings may be transient, and can convert from one type to another and to normal.

Type 1 associated with highest risk.

ECG testing with a sodium channel blocker can change patients from type 2,3 to type 1 pattern, and increase risk of sudden death.

Precipitating factors for Brugada syndrome include fever, ilicit drugs, lithium, and tricyclic antidepressants.

In some countries it is the second most common cause of death in young adults.

ICD is indicated for patients with this syndrome with aborted sudden cardiac death, unexplained syncope, and ventricular tachycardia.

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